__cxx03/__concepts/convertible_to.h

0001 //===----------------------------------------------------------------------===//
0002 //
0003 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
0004 // See https://llvm.org/LICENSE.txt for license information.
0005 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
0006 //
0007 //===----------------------------------------------------------------------===//
0008
0009 #ifndef _LIBCPP___CXX03___CONCEPTS_CONVERTIBLE_TO_H
0010 #define _LIBCPP___CXX03___CONCEPTS_CONVERTIBLE_TO_H
0011
0012 #include <__cxx03/__config>
0013 #include <__cxx03/__type_traits/is_convertible.h>
0014 #include <__cxx03/__utility/declval.h>
0015
0016 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
0017 #  pragma GCC system_header
0018 #endif
0019
0020 _LIBCPP_BEGIN_NAMESPACE_STD
0021
0022 #if _LIBCPP_STD_VER >= 20
0023
0024 // [concept.convertible]
0025
0026 template <class _From, class _To>
0027 concept convertible_to = is_convertible_v<_From, _To> && requires { static_cast<_To>(std::declval<_From>()); };
0028
0029 #endif // _LIBCPP_STD_VER >= 20
0030
0031 _LIBCPP_END_NAMESPACE_STD
0032
0033 #endif // _LIBCPP___CXX03___CONCEPTS_CONVERTIBLE_TO_H